The present invention relates to a plasma processing method and apparatus and more specifically to a plasma processing method and apparatus suited for plasma-processing specimens such as semiconductor device substrates.
There has been available a technique of plasma-processing specimens of semiconductor device substrates, as represented by a technique described in Japanese Patent Laid-Open No. 167825/1991. This publication describes a technique which limits the temperature control of a processing chamber where plasma is generated only to a sidewall portion and deals with only reaction products that are generated after etching.
The above-mentioned technique is effective only for reaction products adhering to the inner surface of the sidewall of the processing chamber and does not consider reaction products or gaseous reaction products adhering the electrodes, i.e., the lower part of the specimen mount, the inner bottom portion of the processing chamber and the exhaust pipe, during the plasma processing.
That is, reaction products also adhere to the lower part of the specimen mount, the inner bottom portion of the processing chamber and the exhaust pipe. During the plasma processing, these reaction products are not only deposited on these portions, but also flake off, thereby contaminating the specimens and greatly reducing the yield of specimens.